Abstract:

A Multiple-Input Multiple-Output (MIMO) relay system is provided. The MIMO
relay system performs signal processing to provide requested real data to
at least one selected user mobile station sequentially connected to a
first relay station located in a first cell and a second relay station
located in a second cell using spare frequency capacity allocated to a
first base station of the first cell instead of a second base station of
the second cell that drops the requested real data due to its frequency
capacity being exceeded, thereby improving reliability of seamless real
data input/output in relay communication, reducing call drop probability,
and raising availability of frequency capacity by automatically adjusting
frequency capacity allocated between cells.

Claims:

1. A Multiple-Input Multiple-Output (MIMO) relay system, comprising:a
first cell;a first Base Station (BS) and a first Relay Station (RS)
located in the first cell;a second cell;a second BS, a second RS, and at
least one selected user Mobile Station (MS) of a plurality of user MSs
located in the second cell,wherein the system processes, when the at
least one user MS requests real data to be received by accessing the
second BS whose frequency capacity has been exceeded, signals to enable
the requested real data to be provided to the at least one user MS
sequentially connected to the first and second RSs using spare frequency
capacity allocated to the first BS instead of the second BS which drops
the requested real data.

2. A Multiple-Input Multiple-Output (MIMO) relay system, comprising:a
first cell;a first Base Station (BS) and a first Relay Station (RS)
located in the first cell;a second cell;a second RS dropping requested N
real data, a second RS, and at least one selected user Mobile Station
(MS) of a plurality of user MSs are located in the second cell;a first
MIMO channel formed between the first BS and the first RS;a second MIMO
channel formed between the first RS and the second RS; anda
Multiple-Input Single-Output (MISO) channel formed between the second RS
and the at least one selected user MS, wherein:the first BS has multiple
transmit antennas in which first transmit antenna interference occurs
when the first MIMO channel is formed and generates and transmits N
different first BS real data after removing user interference generated
by user MSs from the N real data and removes the first transmit antenna
interference from N information values amplified and converted by
applying N different powers in 1:1 correspondence;the first RS has
multiple transmit antennas in which second transmit antenna interference
occurs when the second MIMO channel is formed, transmits N different
first relay real data amplified and converted by applying a first RS
amplification gain to the transmitted N different first BS real data in a
first time slot, and receives the N different first BS real data from the
first BS in a second time slot;the second RS has multiple transmit
antennas in which third transmit antenna interference occurs when the
MISO channel is formed, provides the at least one selected user MS with N
different second relay real data re-amplified and converted by applying a
second RS amplification gain to the transmitted N different first relay
real data in a third time slot, and receives the N different first relay
real data from the first RS in a fourth time slot; andthe first BS
provides the first RS with the N different first BS real data
signal-processed by removing the second and third transmit antenna
interference from the amplified and converted N information values.

3. The MIMO relay system of claim 2, wherein the first BS comprises:a
Zero-Forcing Dirty Paper Coding (ZF-DPC) unit generating N user
interference-removed real data by removing the user interference
generated by the user MSs from the N real data;a first power supply
generating N different power real data amplified and converted by
applying the N different powers to the N user interference-removed real
data in 1:1 correspondence; andan antenna interference detection and
removal unit generating the N different first BS real data
signal-converted by removing all the first, second, and third transmit
antenna interference from the N different power real data.

4. The MIMO relay system of claim 2, wherein the first RS comprises:a
second power supply generating the N different first relay real data
amplified and converted by applying the same first RS amplification gain
to the N different first BS real data.

5. The MIMO relay system of claim 2, wherein the second RS comprises:a
third power supply generating the N different second relay real data
re-amplified and converted by applying the same second RS amplification
gain to the N different first relay real data.

6. The MIMO relay system of claim 5, wherein the N different second relay
real data are N different multimedia information values signal-processed
to be transmitted to the at least one selected user MS corresponding to a
target end via the first BS, the first RS, and the second RS.

7. A Multiple-Input Multiple-Output (MIMO) relay system, comprising:a
first cell;a first Base Station (BS) and a first Relay Station (RS)
located in the first cell;a second cell;a second RS dropping requested N
real data, a second RS, and at least one selected user Mobile Station
(MS) of a plurality of user MSs located in the second cell;a first MIMO
channel formed between the first BS and the first RS;a second MIMO
channel formed between the first RS and the second RS; anda MISO channel
formed between the second RS and the at least one selected user MS,
wherein:the first BS has multiple transmit antennas in which first
transmit antenna interference occurs when the first MIMO channel is
formed, and generates and transmits N different first BS real data after
removing user interference generated by user MSs from the N real data,
and removes the first transmit antenna interference from N information
values amplified and converted by applying N different first powers in
1:1 correspondence;the first RS has multiple transmit and receive
antennas in which receive antenna interference occurs when the first MIMO
channel is formed and second transmit antenna interference occurs when
the second MIMO channel is formed, generates and transmits N different
first relay real data after removing the receive antenna interference
from the transmitted N different first BS real data and removing the
second transmit antenna interference from N second information values
amplified and converted by applying N different second powers in 1:1
correspondence in a first time slot, and receives the N different first
BS real data from the first BS in a second time slot; andthe second RS
has multiple transmit antennas in which third transmit antenna
interference occurs when the MISO channel is formed, provides the at
least one selected user MS with N different second relay real data
re-amplified and converted by applying a second RS amplification gain to
the transmitted N different first relay real data in a third time slot,
and receives the N different first relay real data from the first RS in a
fourth time slot; andthe first RS provides the second RS with the N
different first relay real data signal-processed by removing the third
transmit antenna interference from the amplified and converted N
information values.

8. The MIMO relay system of claim 7, wherein the first BS comprises:a
ZF-DPC unit generating N user interference-removed real data by removing
the user interference generated by the user MSs from the N real data;a
first power supply generating N different first power real data amplified
and converted by applying the N different first powers to the N user
interference-removed real data in 1:1 correspondence; anda first antenna
interference detection and removal unit generating the N different first
BS real data signal-converted by removing the first transmit antenna
interference from the N different first power real data.

9. The MIMO relay system of claim 7, wherein the first RS comprises:a
second antenna interference detection and removal unit generating N
different first relay reception stage interference-removed real data by
removing the receive antenna interference generated by the multiple
receive antennas from the N different first BS real data;a second power
supply generating N different first relay amplification real data
amplified and converted by applying N different second powers to the N
different first relay reception stage interference-removed real data in
1:1 correspondence; anda third antenna interference detection and removal
unit generating the N different first relay real data signal-converted by
removing the second and third transmit antenna interference from the N
different first relay amplification real data.

10. The MIMO relay system of claim 7, wherein the second RS comprises:a
third power supply generating the N different second relay real data
re-amplified and converted by applying the same second RS amplification
gain to the N different first relay real data.

11. The MIMO relay system of claim 10, wherein the N different second
relay real data are N different multimedia information values
signal-processed to be transmitted to the at least one selected user MS
corresponding to a target end via the first BS, the first RS, and the
second RS.

12. A Multiple-Input Multiple-Output (MIMO) relay method for a MIMO relay
system in which a first BS and a first RS are located in a first cell, a
second RS dropping requested N real data, a second RS, and at least one
selected user MS of a plurality of user MSs are located in a second cell,
a first MIMO channel is formed between the first BS and the first RS, a
second MIMO channel is formed between the first RS and the second RS, and
a MISO channel is formed between the second RS and the at least one
selected user MS, the method comprising:generating, by the first BS, N
user interference-removed real data by removing user interference
generated by user MSs from the N real data;generating, by the first BS, N
different first power real data amplified and converted by applying N
different first powers to the N user interference-removed real data in
1:1 correspondence;detecting, by the first BS, first transmit antenna
interference affecting its multiple transmit antennas when the first MIMO
channel is formed;detecting, by the first RS, first receive antenna
interference affecting its multiple receive antennas when the first MIMO
channel is formed and second transmit antenna interference affecting its
multiple transmit antennas when the second MIMO channel is
formed;detecting, by the second RS, second receive antenna interference
affecting its multiple receive antennas when the second MIMO channel is
formed and third transmit antenna interference affecting its multiple
transmit antennas when the MISO channel is formed;providing, by the first
BS, the first RS with N different first BS real data produced by removing
the first transmit antenna interference from the N different first power
real data;generating, by the first RS, N different first relay reception
stage interference-removed real data by removing the first receive
antenna interference from the N different first BS real data;generating,
by the first RS, N different first relay amplification real data
amplified and converted by applying N different second powers to the N
different first relay reception stage interference-removed real data in
1:1 correspondence in a first time slot;providing, by the first RS, the
second RS with N different first relay real data produced by removing the
second transmit antenna interference from the N different first relay
amplification real data;receiving, by the first RS, N different first BS
real data from the first BS in a second time slot;generating, by the
second RS, N different second relay reception stage interference-removed
real data by removing the second receive antenna interference from the
provided N different first relay real data;generating, by the second RS,
N different second relay amplification real data re-amplified and
converted by applying N different third powers to the N different second
relay reception stage interference-removed real data in 1:1
correspondence in a third time slot;providing, by the second RS, the at
least one selected user MS with N different second relay real data
produced by removing the third transmit antenna interference from the N
different second relay amplification real data; andreceiving, by the
second RS, N different first relay real data from the first RS in a
fourth time slot.

13. The MIMO relay method of claim 12, further comprising: in the first
BS,generating, by a ZF-DPC unit, the N user interference-removed real
data by removing the user interference generated by the user MSs from the
N real data.generating, by a first power supply, the N different first
power real data amplified and converted by applying the N different first
powers to the N user interference-removed real data in 1:1
correspondence; andgenerating, by a first antenna interference and
removal unit, generates the N different first BS real data
signal-converted by removing the first transmit antenna interference from
the N different first power real data.

14. The MIMO relay method of claim 12, further comprising: in the first
RS,generating, by a second antenna interference detection and removal
unit, the N different first relay reception stage interference-removed
real data by removing the receive antenna interference generated by its
multiple receive antennas from the N different first BS real
data;generating, by a second power supply, the N different first relay
amplification real data amplified and converted by applying the N
different second powers to the N different first relay reception stage
interference-removed real data in 1:1 correspondence; andgenerating, by a
third antenna interference detection and removal unit, the N different
first relay real data signal-converted by removing the second transmit
antenna interference from the N different first relay amplification real
data.

15. The MIMO relay method of claim 12, further comprising: in the second
RS,generating, by a fourth antenna interference and removal unit, the N
different second relay reception stage interference-removed real data by
removing the receive antenna interference generated by its multiple
receive antennas from the N different first relay real data;generating,
by a third power supply, the N different second relay amplification real
data amplified and converted by applying the N different third powers to
the N different second relay reception stage interference-removed real
data in 1:1 correspondence; andgenerating, by a fifth antenna
interference detection and removal unit, the N different second relay
real data signal-converted by removing the third transmit antenna
interference from the N different second relay amplification real data.

Description:

BACKGROUND OF THE INVENTION

[0001]1. Field of the Invention

[0002]The present invention relates to Multiple-Input Multiple-Output
(MIMO) communication technologies and, more particularly, to a MIMO relay
system and method that perform signal processing to provide requested
real data to at least one selected user Mobile Station (MS) sequentially
connected to a plurality of Relay Stations (RSs) using spare frequency
capacity allocated to another Base Station (BS) instead of a BS that
drops the requested real data due to its frequency capacity being
exceeded.

[0003]2. Description of the Related Art

[0004]In general, a cellular system is configured with small-sized service
areas called cells by dividing the entire service coverage region into a
plurality of BS areas. When a mobile station center (MSC) controls BSs in
a concentrated manner, user mobile stations may continue communication
while on the move between cells.

[0005]In this case, since a plurality of user MSs located in the cellular
system are differently distributed between cells, at least one user MS
may be located in a cell with a BS whose channel capacity has been
exceeded.

[0006]Even when another user MS additionally joins the cell with the BS
whose channel capacity has been exceeded, the BS within the cell does not
accommodate the additional user MS due to the limited channel capacity.

[0007]That is, the conventional cellular system has a problem that call
drop probability increases and spectral efficiency decreases due to
imbalanced channel allocation between the BS with limited channel
capacity and the additional user MS, thereby degrading reliability of a
mobile communication network.

SUMMARY OF THE INVENTION

[0008]The present invention provides a MIMO relay system and method that
can perform signal processing to provide requested real data to at least
one selected user MS sequentially connected to a first RS located in a
first cell and a second RS located in a second cell using spare frequency
capacity allocated to a first BS of the first cell instead of a second BS
of the second cell that drops the requested real data due to its
frequency capacity being exceeded, thereby improving reliability of
seamless real data input/output in relay communication, reducing call
drop probability, and raising availability of frequency capacity by
automatically adjusting frequency capacity allocated between cells.

[0009]According to exemplary embodiments of the present invention, a MIMO
relay system in which a first BS and a first RS are located in a first
cell, and a second BS, a second RS, and at least one selected user MS of
a plurality of user MSs are located in a second cell, includes:
processing, when the at least one user MS requests real data to be
received by accessing the second BS whose frequency capacity has been
exceeded, signals to enable the requested real data to be provided to the
at least one user MS sequentially connected to the first and second RSs
using spare frequency capacity allocated to the first BS instead of the
second BS which drops the requested real data.

[0010]According to a first exemplary embodiment of the present invention,
a MIMO relay system in which a first BS and a first RS are located in a
first cell, a second RS dropping requested N real data, a second RS, and
at least one selected user MS of a plurality of user MSs are located in a
second cell, a first MIMO channel is formed between the first BS and the
first RS, a second MIMO channel is formed between the first RS and the
second RS, and a Multiple-Input Single-Output (MISO) channel is formed
between the second RS and the at least one selected user MS, includes:
the first BS having multiple transmit antennas in which first transmit
antenna interference occurs when the first MIMO channel is formed, and
generating and transmitting N different first BS real data after removing
user interference generated by user MSs from the N real data and removing
the first transmit antenna interference from N information values
amplified and converted by applying N different powers in 1:1
correspondence; the first RS having multiple transmit antennas in which
second transmit antenna interference occurs when the second MIMO channel
is formed, transmitting N different first relay real data amplified and
converted by applying a first RS amplification gain to the transmitted N
different first BS real data in a first time slot, and receiving the N
different first BS real data from the first BS in a second time slot; and
the second RS having multiple transmit antennas in which third transmit
antenna interference occurs when the MISO channel is formed, providing
the at least one selected user MS with N different second relay real data
re-amplified and converted by applying a second RS amplification gain to
the transmitted N different first relay real data in a third time slot,
and receiving the N different first relay real data from the first RS in
a fourth time slot, wherein the first BS provides the first RS with the N
different first BS real data signal-processed by removing the second and
third transmit antenna interference from the amplified and converted N
information values is provided.

[0011]According to a second exemplary embodiment of the present invention,
a MIMO relay system in which a first BS and a first RS are located in a
first cell, a second RS dropping requested N real data, a second RS, and
at least one selected user MS of a plurality of user MSs are located in a
second cell, a first MIMO channel is formed between the first BS and the
first RS, a second MIMO channel is formed between the first RS and the
second RS, and a MISO channel is formed between the second RS and the at
least one selected user MS, includes: the first BS having multiple
transmit antennas in which first transmit antenna interference occurs
when the first MIMO channel is formed, and generating and transmitting N
different first BS real data after removing user interference generated
by user MSs from the N real data and removing the first transmit antenna
interference from N information values amplified and converted by
applying N different first powers in 1:1 correspondence; the first RS
having multiple transmit and receive antennas in which receive antenna
interference occurs when the first MIMO channel is formed and second
transmit antenna interference occurs when the second MIMO channel is
formed, generating and transmitting N different first relay real data
after removing the receive antenna interference from the transmitted N
different first BS real data and removing the second transmit antenna
interference from N second information values amplified and converted by
applying N different second powers in 1:1 correspondence in a first time
slot, and receiving the N different first BS real data from the first BS
in a second time slot; and the second RS having multiple transmit
antennas in which third transmit antenna interference occurs when the
MISO channel is formed, providing the at least one selected user MS with
N different second relay real data re-amplified and converted by applying
a second RS amplification gain to the transmitted N different first relay
real data in a third time slot, and receiving the N different first relay
real data from the first RS in a fourth time slot, wherein the first RS
provides the second RS with the N different first relay real data
signal-processed by removing the third transmit antenna interference from
the amplified and converted N information values is provided.

[0012]Preferably, the first BS comprises: a Zero-Forcing Dirty Paper
Coding (ZF-DPC) unit generating N user interference-removed real data by
removing the user interference generated by the user MSs from the N real
data; a first power supply generating N different power real data
amplified and converted by applying the N different powers to the N user
interference-removed real data in 1:1 correspondence; and an antenna
interference detection and removal unit generating the N different first
BS real data signal-converted by removing all the first, second, and
third transmit antenna interference from the N different power real data.

[0013]Preferably, the first RS comprises: a second power supply generating
the N different first relay real data amplified and converted by applying
the same first RS amplification gain to the N different first BS real
data.

[0014]Preferably, the second RS comprises: a third power supply generating
the N different second relay real data re-amplified and converted by
applying the same second RS amplification gain to the N different first
relay real data.

[0015]Preferably, the N different second relay real data are N different
multimedia information values signal-processed to be transmitted to the
at least one selected user MS corresponding to a target end via the first
BS, the first RS, and the second RS.

[0016]According to a third exemplary embodiment of the present invention,
a MIMO relay method in which a first BS and a first RS are located in a
first cell, a second RS dropping requested N real data, a second RS, and
at least one selected user MS of a plurality of user MSs are located in a
second cell, a first MIMO channel is formed between the first BS and the
first RS, a second MIMO channel is formed between the first RS and the
second RS, and a MISO channel is formed between the second RS and the at
least one selected user MS, includes: generating, by the first BS, N user
interference-removed real data by removing user interference generated by
user MSs from the N real data; generating, by the first BS, N different
first power real data amplified and converted by applying N different
first powers to the N user interference-removed real data in 1:1
correspondence; detecting, by the first BS, first transmit antenna
interference affecting its multiple transmit antennas when the first MIMO
channel is formed; detecting, by the first RS, first receive antenna
interference affecting its multiple receive antennas when the first MIMO
channel is formed and second transmit antenna interference affecting its
multiple transmit antennas when the second MIMO channel is formed;
detecting, by the second RS, second receive antenna interference
affecting its multiple receive antennas when the second MIMO channel is
formed and third transmit antenna interference affecting its multiple
transmit antennas when the MISO channel is formed; providing, by the
first BS, the first RS with N different first BS real data produced by
removing the first transmit antenna interference from the N different
first power real data; generating, by the first RS, N different first
relay reception stage interference-removed real data by removing the
first receive antenna interference from the N different first BS real
data; generating, by the first RS, N different first relay amplification
real data amplified and converted by applying N different second powers
to the N different first relay reception stage interference-removed real
data in 1:1 correspondence in a first time slot; providing, by the first
RS, the second RS with N different first relay real data produced by
removing the second transmit antenna interference from the N different
first relay amplification real data; receiving, by the first RS, N
different first BS real data from the first BS in a second time slot;
generating, by the second RS, N different second relay reception stage
interference-removed real data by removing the second receive antenna
interference from the provided N different first relay real data;
generating, by the second RS, N different second relay amplification real
data re-amplified and converted by applying N different third powers to
the N different second relay reception stage interference-removed real
data in 1:1 correspondence in a third time slot; providing, by the second
RS, the at least one selected user MS with N different second relay real
data produced by removing the third transmit antenna interference from
the N different second relay amplification real data; and receiving, by
the second RS, N different first relay real data from the first RS in a
fourth time slot is provided.

[0017]Preferably, the first BS comprises: a ZF-DPC unit generating N user
interference-removed real data by removing the user interference
generated by the user MSs from the N real data; a first power supply
generating N different first power real data amplified and converted by
applying the N different first powers to the N user interference-removed
real data in 1:1 correspondence; and a first antenna interference
detection and removal unit generating the N different first BS real data
signal-converted by removing the first transmit antenna interference from
the N different first power real data.

[0018]Preferably, the first RS comprises: a second antenna interference
detection and removal unit generating N different first relay reception
stage interference-removed real data by removing the receive antenna
interference generated by the multiple receive antennas from the N
different first BS real data; a second power supply generating N
different first relay amplification real data amplified and converted by
applying N different second powers to the N different first relay
reception stage interference-removed real data in 1:1 correspondence; and
a third antenna interference detection and removal unit generating the N
different first relay real data signal-converted by removing the second
and third transmit antenna interference from the N different first relay
amplification real data.

[0019]Preferably, the second RS comprises: a third power supply generating
the N different second relay real data re-amplified and converted by
applying the same second RS amplification gain to the N different first
relay real data.

[0020]Preferably, the N different second relay real data are N different
multimedia information values signal-processed to be transmitted to the
at least one selected user MS corresponding to a target end via the first
BS, the first RS, and the second RS.

[0021]According to a fourth embodiment of the present invention, a MIMO
relay method in which a first BS and a first RS are located in a first
cell, a second RS dropping requested N real data, a second RS, and at
least one selected user MS of a plurality of user MSs are located in a
second cell, a first MIMO channel is formed between the first BS and the
first RS, a second MIMO channel is formed between the first RS and the
second RS, and a MISO channel is formed between the second RS and the at
least one selected user MS, the method comprising:

[0022]generating, by the first BS, N user interference-removed real data
by removing user interference generated by user MSs from the N real data;
generating, by the first BS, N different first power real data amplified
and converted by applying N different first powers to the N user
interference-removed real data in 1:1 correspondence; detecting, by the
first BS, first transmit antenna interference affecting its multiple
transmit antennas when the first MIMO channel is formed; detecting, by
the first RS, first receive antenna interference affecting its multiple
receive antennas when the first MIMO channel is formed and second
transmit antenna interference affecting its multiple transmit antennas
when the second MIMO channel is formed; detecting, by the second RS,
second receive antenna interference affecting its multiple receive
antennas when the second MIMO channel is formed and third transmit
antenna interference affecting its multiple transmit antennas when the
MISO channel is formed; providing, by the first BS, the first RS with N
different first BS real data produced by removing the first transmit
antenna interference from the N different first power real data;
generating, by the first RS, N different first relay reception stage
interference-removed real data by removing the first receive antenna
interference from the N different first BS real data; generating, by the
first RS, N different first relay amplification real data amplified and
converted by applying N different second powers to the N different first
relay reception stage interference-removed real data in 1:1
correspondence in a first time slot; providing, by the first RS, the
second RS with N different first relay real data produced by removing the
second transmit antenna interference from the N different first relay
amplification real data; receiving, by the first RS, N different first BS
real data from the first BS in a second time slot; generating, by the
second RS, N different second relay reception stage interference-removed
real data by removing the second receive antenna interference from the
provided N different first relay real data; generating, by the second RS,
N different second relay amplification real data re-amplified and
converted by applying N different third powers to the N different second
relay reception stage interference-removed real data in 1:1
correspondence in a third time slot; providing, by the second RS, the at
least one selected user MS with N different second relay real data
produced by removing the third transmit antenna interference from the N
different second relay amplification real data; and receiving, by the
second RS, N different first relay real data from the first RS in a
fourth time slot is provided.

[0023]Preferably, the method further comprises: in the first BS,
generating, by a ZF-DPC unit, the N user interference-removed real data
by removing the user interference generated by the user MSs from the N
real data, generating, by a first power supply, the N different first
power real data amplified and converted by applying the N different first
powers to the N user interference-removed real data in 1:1
correspondence; and generating, by a first antenna interference and
removal unit, generates the N different first BS real data
signal-converted by removing the first transmit antenna interference from
the N different first power real data.

[0024]Preferably, the method further comprises: in the first RS,
generating, by a second antenna interference detection and removal unit,
the N different first relay reception stage interference-removed real
data by removing the receive antenna interference generated by its
multiple receive antennas from the N different first BS real data;
generating, by a second power supply, the N different first relay
amplification real data amplified and converted by applying the N
different second powers to the N different first relay reception stage
interference-removed real data in 1:1 correspondence; and generating, by
a third antenna interference detection and removal unit, the N different
first relay real data signal-converted by removing the second transmit
antenna interference from the N different first relay amplification real
data.

[0025]Preferably, the method further comprises: in the second RS,
generating, by a fourth antenna interference and removal unit, the N
different second relay reception stage interference-removed real data by
removing the receive antenna interference generated by its multiple
receive antennas from the N different first relay real data; generating,
by a third power supply, the N different second relay amplification real
data amplified and converted by applying the N different third powers to
the N different second relay reception stage interference-removed real
data in 1:1 correspondence; and generating, by a fifth antenna
interference detection and removal unit, the N different second relay
real data signal-converted by removing the third transmit antenna
interference from the N different second relay amplification real data.

BRIEF DESCRIPTION OF THE DRAWINGS

[0026]The above and other objects, features and advantages of the present
invention will become more apparent to those of ordinary skill in the art
by describing in detail exemplary embodiments thereof with reference to
the accompanying drawings, in which:

[0027]FIG. 1 shows a MIMO relay system on a mobile communication network
according to exemplary embodiments of the present invention;

[0028]FIG. 2 is a block diagram of a MIMO relay system on a mobile
communication network according to a first exemplary embodiment of the
present invention;

[0029]FIG. 3 is a flowchart showing a MIMO relay method on the mobile
communication network according to the first exemplary embodiment of the
present invention;

[0030]FIG. 4 is a block diagram of a MIMO relay system on a mobile
communication network according to a second exemplary embodiment of the
present invention;

[0031]FIG. 5 is a flowchart showing a MIMO relay method on the mobile
communication network according to the second exemplary embodiment of the
present invention;

[0032]FIG. 6 is a block diagram of a MIMO relay system on a mobile
communication network according to a third exemplary embodiment of the
present invention; and

[0033]FIG. 7 is a flowchart showing a MIMO relay method on the mobile
communication network according to the third exemplary embodiment of the
present invention.

DETAILED DESCRIPTION OF EXEMPLARY EMBODIMENTS

[0034]The invention is described more fully hereinafter with reference to
the accompanying drawings, in which exemplary embodiments of the
invention are shown.

[0035]FIG. 1 shows a MIMO relay system on a mobile communication network
according to exemplary embodiments of the present invention.

[0036]Referring to FIG. 1, a MIMO relay system 1000 includes a first BS
100, a second BS 500, a first RS 200, a second RS 300, and at least one
selected user MS 400.

[0037]When at least one selected user MS 400 requests real data by
accessing the second BS 500 whose allocated frequency capacity has been
exceeded by use of a plurality of user MSs, the second BS 500 drops
requested real data transmission due to its frequency capacity having
been exceeded and the first BS 100 of a first cell provides at least one
selected user MS 400 with the real data to be transmitted via the first
RS 200 located in the first cell and the second RS 300 located in a
second cell using a spare of allocated frequency capacity of the first BS
100. Therefore, the MIMO relay system 1000 can improve reliability of
seamless real data input/output in relay communication, reduce call drop
probability, and raise availability of frequency capacity by
automatically adjusting frequency capacity allocated between cells.

[0038]Exemplary embodiments of the present invention are performed when at
least one selected user MS 400 does not directly receive real data from
the second BS 500 since the at least one selected user MS 400 is far away
from the second BS 500 of the second cell including the at least one
selected user MS 400, the second BS 500 whose allocated frequency
capacity has been exceeded by use of a plurality of user MSs, or the at
least one selected user MS 400 is located in a shadow area.

[0039]That is, the first BS 200 located in the first cell allocates
available frequency capacity to the at least one selected user MS 400
located in the second cell, thereby enabling the user MS 400 to receive
the real data via the first and second RSs.

[0040]Even when a distance between the second BS and the at least one
selected user MS located in the same second cell is far, the second BS
transmits the real data to the user MS 400 using the first and second RSs
200 and 300.

[0041]FIG. 2 is a block diagram of a MIMO relay system on a mobile
communication network according to a first exemplary embodiment of the
present invention.

[0042]Referring to FIG. 2, a MIMO relay system 1000 according to the first
exemplary embodiment includes a first BS (BS1) 100 having multiple
transmit/receive antennas in a first cell, a first RS (RS1) 200 having
multiple transmit/receive antennas in the first cell, a second RS (RS2)
300 having multiple transmit/receive antennas in a second cell, and a
user MS 400 located in the second cell.

[0043]The MIMO relay system 1000 further includes a second BS (BS2) 500
having multiple antennas in the second cell.

[0044]A first MIMO channel H1 is formed between the first BS 100 and
the first RS 200 belonging to the first cell. A second MIMO channel
H2 is formed between the first RS 200 belonging to the first cell
and the second RS 300 belonging to the second cell.

[0045]A multiple-input single-output (MISO) channel H3 is formed
between the second RS 300 and the user MS 400.

[0046]When the first BS 100 transmits a payload or real data containing N
different multimedia information values to the user MS 400 located in the
second cell in a mobile communication environment according to the first
exemplary embodiment of the present invention, user interference
generated from a plurality of user MSs located in the second cell is
first removed by applying the user interference to a Zero-Forcing Dirty
Paper Coding (ZF-DPC) unit 110.

[0047]The first BS 100 provides the first RS 200 located in the first cell
with N user interference-removed real data converted and generated by
removing the user interference from N real data by applying N different
powers P1, P2, - - - , PN to the N user
interference-removed real data in 1:1 correspondence.

[0048]The N user interference-removed real data are amplified and
converted into N different power real data by a composite operation with
the N different powers P1, P2, - - - , PN provided from a
first power supply 120 of the first BS 100 in 1:1 correspondence.

[0049]When the first and second MIMO channels H1 and H2 and the
MISO channel H3 are formed, the first BS 100 detects first, second,
and third transmit antenna interference affecting multiple transmit
antennas provided in the first BS 100, the first RS 200, and the second
RS 300 through an internally configured antenna interference detection
and removal unit 130.

[0050]The first BS 100 generates N different first BS real data
signal-converted by removing all the first, second, and third transmit
antenna interference from the N different power real data using the
antenna interference detection and removal unit 130, and provides the
first RS 200 located in the first cell with the N different first BS real
data.

[0051]The first RS 200 processes the N different first BS real data
signal-converted and transmitted from the first BS 100 using a
half-duplex communication mode in which transmission and reception are
time-divided and an Amplify-and-Forward (AF) mode.

[0052]That is, the first RS 200 performs signal amplification by applying
a first RS amplification gain g1 corresponding to the same transmit
power value provided from an internally configured second power supply to
the N different first BS real data received from the first BS 100 in a
first time slot ts1.

[0053]The first RS 200 generates N different first relay real data
converted and processed by the signal amplification and transmits the N
different first relay real data to the second RS 300.

[0054]In a second time slot ts2, the first RS 200 receives N different
first BS real data from the first BS 100.

[0055]In summary, the first RS 200 transmits the N different first relay
real data to the second RS 300 by amplifying the N different first BS
real data transmitted from the first BS 100 in the half-duplex
communication mode and the AF mode in the first time slot ts1.

[0056]In the second time slot ts2, the first RS 200 receives N different
first BS real data from the first BS 100.

[0057]Subsequently, the second RS 300 located in the second cell directly
follows the half-duplex communication mode and the AF mode applied to the
first RS 200.

[0058]Since the first RS amplification gain g1 applied to the N
different first relay real data input from the first RS 200 has been
consumed during relay transmission, the second RS 300 newly applies a
second RS amplification gain g2 required for re-amplification and
transmission to the user MS 400 to the N different first relay real data
received from the first RS 200.

[0059]That is, the second RS 300 performs signal re-amplification by
applying the second RS amplification gain g2 corresponding to the
same transmit power value provided from an internally configured third
power supply to the N different first relay real data received from the
first RS 200 in the first time slot ts1.

[0060]The second RS 300 generates N different second relay real data
converted and processed by the signal re-amplification and transmits the
N different second relay real data to the user MS 400 located in the
second cell.

[0061]In the second time slot ts2, the second RS 300 receives N different
first relay real data from the first RS 200.

[0062]Here, the N different second relay real data are N different
multimedia information values whose signals have been processed to be
transmitted to at least one selected user MS corresponding to a target
end via the first BS, the first RS, and the second RS.

[0063]In summary, the second RS 300 transmits the N different second relay
real data to the user MS 400 located in the second cell by amplifying the
N different first relay real data transmitted from the first RS 200 in
the half-duplex communication mode and the AF mode in the first time slot
ts1.

[0064]In the second time slot ts2, the second RS 300 receives N different
first relay real data from the first RS 200.

[0065]FIG. 3 is a flowchart showing a MIMO relay method on the mobile
communication network according to the first exemplary embodiment of the
present invention.

[0066]Referring to FIG. 3, the MIMO relay method of the first exemplary
embodiment operates in a mobile communication environment where the first
BS and the first RS are included in the first cell, the second RS and a
plurality of user MSs are included in the second cell, the first MIMO
channel is formed between the first BS and the first RS, the second MIMO
channel is formed between the first RS and the second RS, or the MISO
channel is formed between the second RS and at least one selected user MS
of the user MSs as follows.

[0067]First, the first BS generates N user interference-removed real data
by removing user interference generated by multiple user MSs from N real
data to be transmitted to the at least one selected user MS (S10).

[0068]The first BS generates N different power real data amplified and
converted by applying N different powers to the N user
interference-removed real data in 1:1 correspondence (S20).

[0069]When the first MIMO channel is formed, the first BS detects first
transmit antenna interference affecting its multiple transmit antennas
(S30).

[0070]When the second MIMO channel is formed, the first RS detects second
transmit antenna interference affecting its multiple transmit antennas
(S40).

[0071]When the MISO channel is formed, the second RS detects third
transmit antenna interference affecting its multiple transmit antennas
(S50).

[0072]The first BS provides the first RS with N different first BS real
data produced by removing all the first, second, and third transmit
antenna interference from the N different power real data (S60).

[0073]The first RS provides an outside device with N different first relay
real data amplified and converted by applying the same first RS
amplification gain to the transmitted N different first BS real data in a
first time slot (S70).

[0074]The first RS receives N different first BS real data from the first
BS in time division in a second time slot (S80).

[0075]The second RS provides at least one selected user MS with N
different second relay real data re-amplified and converted by applying
the same second RS amplification gain to the N transmitted different
first relay real data in a third time slot (S90).

[0076]The second RS receives N different first relay real data from the
first RS in time division in a fourth time slot (S100).

[0077]Additional operations of devices configured inside the first BS, the
first RS, and the second RS are as follows.

[0078]The first BS internally includes a ZF-DPC unit, a first power
supply, and an antenna interference detection and removal unit.

[0080]The antenna interference and removal unit generates N different
first BS real data signal-converted by removing all first, second, and
third transmit antenna interference from the N different power real data.

[0081]The first RS internally includes a second power supply, and the
second RS internally includes a third power supply.

[0082]The second power supply of the first RS generates N different first
relay real data amplified and converted by applying the same first RS
amplification gain to the N different first BS real data. The third power
supply of the second RS generates N different second relay real data
re-amplified and converted by applying the same second RS amplification
gain to the N different first relay real data.

[0083]FIG. 4 is a block diagram of a MIMO relay system on a mobile
communication network according to a second exemplary embodiment of the
present invention.

[0084]Referring to FIG. 4, a MIMO relay system 1000 according to the
second exemplary embodiment has the same components as described in the
first exemplary embodiment and includes a first BS (BS1) 100 having
multiple transmit/receive antennas in a first cell, a first RS (RS1) 200
having multiple transmit/receive antennas in the first cell, a second RS
(RS2) 300 having multiple transmit/receive antennas in a second cell, and
a user MS 400 located in the second cell.

[0085]The MIMO relay system 1000 further includes a second BS (BS2) 500
having multiple antennas in the second cell.

[0086]A first MIMO channel H1 is formed between the first BS 100 and
the first RS 200 belonging to the first cell. A second MIMO channel
H2 is formed between the first RS 200 belonging to the first cell
and the second RS 300 belonging to the second cell.

[0087]A MISO channel H3 is formed between the second RS 300 and the
user MS 400.

[0088]In a communication environment having the same conditions as in the
first exemplary embodiment, a signal processing process in the MIMO relay
system 1000 according to the second exemplary embodiment is different
from that described in the first exemplary embodiment.

[0089]That is, when the first BS 100 transmits real data to the user MS
400 located in the second cell, a relay and signal processing method of
the first or second RS 200 or 300 is different from the first exemplary
embodiment.

[0090]When the first BS 100 according to the second exemplary embodiment
of the present invention transmits a payload or real data containing N
different multimedia information values to the user MS 400 located in the
second cell, user interference generated from user MSs located in the
second cell is first removed by applying the user interference to a
ZF-DPC unit 110.

[0091]The first BS 100 provides the first RS 200 located in the first cell
with N user interference-removed real data converted and generated by
removing the user interference from N real data by applying N different
powers P1, P2, - - - , PN to the N user
interference-removed real data in 1:1 correspondence.

[0092]The N user interference-removed real data are amplified and
converted into N different power real data by a composite operation with
the N different powers P1, P2, - - - , PN provided from a
first power supply 120 of the first BS 100 in 1:1 correspondence.

[0093]When the first MIMO channel H1 is formed, the first BS 100
detects first transmit antenna interference affecting its multiple
transmit antennas through an internally configured first antenna
interference detection and removal unit 130.

[0094]The first BS 100 generates N different first BS real data
signal-converted by removing the first transmit antenna interference from
the N different power real data using the first antenna interference
detection and removal unit 130 and provides the first RS 200 located in
the first cell with the N different first BS real data.

[0095]Subsequently, when the first MIMO channel H1 is formed with the
first BS 100, the first RS 200 detects receive antenna interference
affecting its multiple receive antennas through an internally configured
second antenna interference detection and removal unit 210.

[0096]The first RS 200 generates N different first relay reception stage
interference-removed real data signal-converted by removing the receive
antenna interference from the N different first BS real data using the
second antenna interference detection and removal unit 210.

[0097]The first RS 200 processes signals of the N different first relay
reception stage interference-removed real data corresponding to result
values of the previous step using a half-duplex communication mode in
which transmission and reception are time-divided and an AF mode.

[0098]In a first time slot ts1, the first RS 200 performs signal
amplification by applying N different powers k11, k12, - - - ,
k1N provided from an internally configured second power supply 220
to the N different first relay reception stage interference-removed real
data in 1:1 correspondence.

[0099]When the second MIMO channel H2 and the MISO channel H3
are formed after generating N different first relay amplification real
data converted and processed by the signal amplification, the first RS
200 detects second and third transmit antenna interference affecting
multiple transmit antennas of the first and second RSs 200 and 300
through an internally configured third antenna interference detection and
removal unit 230.

[0100]The first RS 200 generates N different first relay real data
signal-converted by removing the second and third transmit antenna
interference from the N different first relay amplification real data
using the third antenna interference detection and removal unit 230, and
provides the second RS 300 located in the second cell with the N
different first relay real data.

[0101]In a second time slot ts2, the first RS 200 receives N different
first BS real data from the first BS 100.

[0102]In summary, the first RS 200 according to the second exemplary
embodiment of the present invention applies the half-duplex communication
mode and the AF mode, removes the receive antenna interference from the N
different first BS real data transmitted from the first BS 100, performs
signal amplification by the N different powers k11, k12, - - -
, k1N in 1:1 correspondence in the first time slot ts1, and provides
the second RS 300 with the N different first relay real data from which
the second and third transmit antenna interference has been removed.

[0103]In the second time slot ts2, the first RS 200 receives N different
first BS real data from the first BS 100.

[0104]Subsequently, the second RS 300 located in the second cell directly
follows the half-duplex communication mode and the AF mode applied to the
first RS 200.

[0105]Since the N different powers k11, k12, - - - , k1N
applied to the N different first relay real data input from the first RS
200 have been consumed, the second RS 300 newly applies a second RS
amplification gain g2 required for re-amplification and transmission
to the user MS 400 to the N different first relay real data.

[0106]That is, the second RS 300 performs signal re-amplification by
applying the second RS amplification gain g2 corresponding to the
same transmit power value provided from an internally configured third
power supply 310 to the N different first relay real data received from
the first RS 200 in the first time slot ts1.

[0107]The second RS 300 generates N different second relay real data
converted by the signal re-amplification and transmits the N different
second relay real data to the user MS 400 located in the second cell.

[0108]In the second time slot ts2, the second RS 300 receives N different
first relay real data from the first RS 200.

[0109]Here, the N different second relay real data are N different
multimedia information values whose signals have been processed to be
transmitted to at least one selected user MS corresponding to a target
end via the first BS, the first RS, and the second RS.

[0110]In summary, the second RS 300 applies the half-duplex communication
mode and the AF mode and transmits the N different second relay real data
to the user MS 400 located in the second cell by amplifying the N
different first relay real data transmitted from the first RS 200 in the
first time slot st1.

[0111]In the second time slot ts2, the second RS 300 receives N different
first relay real data from the first RS 200.

[0112]FIG. 5 is a flowchart showing a MIMO relay method on the mobile
communication network according to the second exemplary embodiment of the
present invention.

[0113]Referring to FIG. 5, the MIMO relay method of the second exemplary
embodiment operates in a mobile communication environment where the first
BS and the first RS are included in the first cell, the second RS and a
plurality of user MSs are included in the second cell, the first MIMO
channel is formed between the first BS and the first RS, the second MIMO
channel is formed between the first RS and the second RS, or the MISO
channel is formed between the second RS and at least one selected user MS
of the user MSs as follows.

[0114]First, the first BS generates N user interference-removed real data
by removing user interference generated by multiple user MSs from N real
data to be transmitted to the at least one selected user MS (S10').

[0115]The first BS generates N different first power real data amplified
and converted by applying N different first powers to the N user
interference-removed real data in 1:1 correspondence (S20').

[0116]When the first MIMO channel is formed, the first BS detects first
transmit antenna interference affecting its multiple transmit antennas
(S30').

[0117]The first RS detects receive antenna interference affecting its
multiple receive antennas when the first MIMO channel is formed and
second transmit antenna interference affecting its multiple transmit
antennas when the second MIMO channel is formed (S40').

[0118]When the MISO channel is formed, the second RS detects third
transmit antenna interference affecting its multiple transmit antennas
(S50').

[0119]The first BS provides the first RS with N different first BS real
data produced by removing the first transmit antenna interference from
the N different first power real data (S60').

[0120]The first RS generates N different first relay reception stage
interference-removed real data by removing the receive antenna
interference from the N different first BS real data (S70').

[0121]The first RS generates N different first relay amplification real
data amplified and converted by applying N different second powers to the
N different first relay reception stage interference-removed real data in
1:1 correspondence in a first time slot (S80').

[0122]The first RS provides the second RS with N different first relay
real data produced by removing the second and third transmit antenna
interference from N different first relay amplification real data (S90').

[0123]The first RS receives N different first BS real data from the first
BS in time division in a second time slot (S100').

[0124]The second RS provides at least one selected user MS with N
different second relay real data re-amplified and converted by applying
the same second RS amplification gain to the transmitted N different
first relay real data in a third time slot (S110').

[0125]The second RS receives N different first relay real data from the
first RS in time division in a fourth time slot (S120').

[0126]Additional operations of devices configured inside the first BS, the
first RS, and the second RS are as follows.

[0127]The first BS internally includes a ZF-DPC unit, a first power
supply, and a first antenna interference detection and removal unit.

[0129]The first power supply generates N different first power real data
amplified and converted by applying N different first powers to the N
user interference-removed real data in 1:1 correspondence.

[0130]The first antenna interference and removal unit generates N
different first BS real data signal-converted by removing first transmit
antenna interference from the N different first power real data.

[0131]The first RS internally includes a second antenna interference
detection and removal unit, a second power supply, and a third antenna
interference and removal unit. The second RS includes a third power
supply.

[0132]The second antenna interference detection and removal unit of the
first RS generates N different first relay reception stage
interference-removed real data by removing receive antenna interference
generated by multiple receive antennas from the N different first BS real
data.

[0133]The second power supply generates N different first relay
amplification real data amplified and converted by applying N different
second powers to the N different first relay reception stage
interference-removed real data in 1:1 correspondence.

[0134]The third antenna interference detection and removal unit generates
N different first relay real data signal-converted by removing second and
third transmit antenna interference from the N different first relay
amplification real data.

[0135]The third power supply of the second RS generates N different second
relay real data re-amplified and converted by applying the same second RS
amplification gain to the N different first relay real data.

[0136]FIG. 6 is a block diagram of a MIMO relay system on a mobile
communication network according to a third exemplary embodiment of the
present invention.

[0137]Referring to FIG. 6, a MIMO relay system 1000 according to the third
exemplary embodiment has the same components as described in the first
and second exemplary embodiments and includes a first BS 100 having
multiple transmit/receive antennas in a first cell, a first RS 200 having
multiple transmit/receive antennas in the first cell, a second RS 300
having multiple transmit/receive antennas in a second cell, and a user MS
400 located in the second cell.

[0138]The MIMO relay system 1000 further includes a second BS 500 having a
plurality of antennas in the second cell.

[0139]A first MIMO channel H1 is formed between the first BS 100 and
the first RS 200 belonging to the first cell. A second MIMO channel
H2 is formed between the first RS 200 belonging to the first cell
and the second RS 300 belonging to the second cell.

[0140]A MISO channel H3 is formed between the second RS 300 and the
user MS 400.

[0141]In a communication environment having the same conditions as the
first and second exemplary embodiments, a signal processing process in
the MIMO relay system 1000 according to the third exemplary embodiment is
different from those described in the first and second exemplary
embodiments.

[0142]That is, when the first BS 100 transmits real data to the user MS
400 located in the second cell, a relay and signal processing method of
the first or second RS 200 or 300 is different from the first and second
exemplary embodiments.

[0143]When the first BS 100 according to the third exemplary embodiment of
the present invention transmits a payload or real data containing N
different multimedia information values to the user MS 400 located in the
second cell, user interference generated from user MSs located in the
second cell is first removed by applying the user interference to a
ZF-DPC unit 110.

[0144]The first BS 100 provides the first RS 200 located in the first cell
with N user interference-removed real data converted and generated by
removing the user interference from N real data by applying N different
powers P1, P2, - - - , PN to the N user
interference-removed real data in 1:1 correspondence.

[0145]The N user interference-removed real data are amplified and
converted into N different power real data by a composite operation with
the N different powers P1, P2, - - - , PN provided from a
first power supply 120 of the first BS 100 in 1:1 correspondence.

[0146]When the first MIMO channel H1 is formed, the first BS 100
detects first transmit antenna interference affecting its multiple
transmit antennas through an internally configured first antenna
interference detection and removal unit 130.

[0147]The first BS 100 generates N different first BS real data
signal-converted by removing the first transmit antenna interference from
the N different power real data using the first antenna interference
detection and removal unit 130 and provides the first RS 200 located in
the first cell with the N different first BS real data.

[0148]Subsequently, when the first MIMO channel H1 is formed with the
first BS 100, the first RS 200 detects receive antenna interference
affecting its multiple receive antennas through an internally configured
second antenna interference detection and removal unit 210.

[0149]The first RS 200 generates N different first relay reception stage
interference-removed real data signal-converted by removing the receive
antenna interference from the N different first BS real data using the
second antenna interference detection and removal unit 210.

[0150]The first RS 200 processes signals of the N different first relay
reception stage interference-removed real data corresponding to result
values of the previous step using a half-duplex communication mode in
which transmission and reception are time-divided and an AF mode.

[0151]In a first time slot ts1, the first RS 200 performs signal
amplification by applying N different powers k11, k12, - - - ,
k1N provided from an internally configured second power supply 220
to the N different first relay reception stage interference-removed real
data in 1:1 correspondence.

[0152]When the second MIMO channel H2 is formed after generating N
different first relay amplification real data converted and processed by
the signal amplification, the first RS 200 detects second transmit
antenna interference affecting its multiple transmit antennas through an
internally configured third antenna interference detection and removal
unit 230.

[0153]The first RS 200 generates N different first relay real data
signal-converted by removing the second transmit antenna interference
from the N different first relay amplification real data using the third
antenna interference detection and removal unit 230 and provides the
second RS 300 located in the second cell with the N different first relay
real data.

[0154]In a second time slot ts2, the first RS 200 receives N different
first BS real data from the first BS 100.

[0155]In summary, the first RS 200 according to the third exemplary
embodiment of the present invention applies the half-duplex communication
mode and the AF mode, removes the receive antenna interference from the N
different first BS real data transmitted from the first BS 100, performs
signal amplification by the N different powers k11, k12, - - -
, k1N in 1:1 correspondence in the first time slot ts1, and provides
the second RS 300 with the N different first relay real data from which
the second transmit antenna interference has been removed.

[0156]In the second time slot ts2, the first RS 200 receives N different
first BS real data from the first BS 100.

[0157]Subsequently, when the second MIMO channel H2 is formed with
the first RS 200, the second RS 300 detects receive antenna interference
affecting its multiple receive antennas through an internally configured
fourth antenna interference detection and removal unit 310.

[0159]The second RS 300 located in the second cell directly follows the
half-duplex communication mode and the AF mode applied to the first RS
200.

[0160]Since the N different powers k11, k12, - - - , k1N
applied to the N different first relay real data input applied by the
first RS 200 have been consumed, the second RS 300 performs signal
re-amplification by applying N different powers k21, k22, - - -
, k2N provided from an internally configured third power supply 320
to the second relay reception stage interference-removed real data in 1:1
correspondence in the first time slot ts1.

[0161]When the MISO channel H3 is formed after generating N different
second relay amplification real data converted and processed by the
signal amplification, the second RS 300 detects third transmit antenna
interference affecting its multiple transmit antennas through an
internally configured fifth antenna interference detection and removal
unit 330.

[0162]The second RS 300 generates N different second relay real data
signal-converted by removing the third transmit antenna interference from
the N different second relay amplification real data using the fifth
antenna interference detection and removal unit 330 and transmits the N
different second relay real data to the user MS 400 located in the second
cell.

[0163]In the second time slot ts2, the second RS 300 receives N different
first relay real data from the first RS 200.

[0164]Here, the N different second relay real data are N different
multimedia information values whose signals have been processed to be
transmitted to at least one selected user MS corresponding to a target
end via the first BS, the first RS, and the second RS.

[0165]In summary, the second RS 300 according to the third exemplary
embodiment of the present invention applies the half-duplex communication
mode and the AF mode, removes the receive antenna interference from the N
different first relay real data transmitted from the first RS 200,
performs signal amplification by the N different powers k21,
k22, - - - , k2N in 1:1 correspondence in the first time slot
ts1, and provides the user MS 400 with the N different second relay real
data from which the third transmit antenna interference has been removed.

[0166]In the second time slot ts2, the second RS 300 receives N different
first relay real data from the first RS 200.

[0167]FIG. 7 is a flowchart showing a MIMO relay method on the mobile
communication network according to the third exemplary embodiment of the
present invention.

[0168]Referring to FIG. 7, the MIMO relay method of the third exemplary
embodiment operates in a mobile communication environment where the first
BS and the first RS are included in the first cell, the second RS and a
plurality of user MSs are included in the second cell, the first MIMO
channel is formed between the first BS and the first RS, the second MIMO
channel is formed between the first RS and the second RS, or the MISO
channel is formed between the second RS and at least one selected user MS
of the user MSs as follows.

[0169]First, the first BS generates N user interference-removed real data
by removing user interference generated by multiple user MSs from N real
data to be transmitted to the at least one selected user MS (S10'').

[0170]The first BS generates N different first power real data amplified
and converted by applying N different first powers to the N user
interference-removed real data in 1:1 correspondence (S20'').

[0171]When the first MIMO channel is formed, the first BS detects first
transmit antenna interference affecting its multiple transmit antennas
(S30'').

[0172]The first RS detects first receive antenna interference affecting
its multiple receive antennas when the first MIMO channel is formed and
second transmit antenna interference affecting its multiple transmit
antennas when the second MIMO channel is formed (S40'').

[0173]The second RS detects second receive antenna interference affecting
its multiple receive antennas when the second MIMO channel is formed and
third transmit antenna interference affecting its multiple transmit
antennas when the MISO channel is formed (S50'').

[0174]The first BS provides the first RS with N different first BS real
data produced by removing the first transmit antenna interference from
the N different first power real data (S60'').

[0175]The first RS generates N different first relay reception stage
interference-removed real data by removing the first receive antenna
interference from the transmitted N different first BS real data (S70'').

[0176]The first RS generates N different first relay amplification real
data amplified and converted by applying N different second powers to the
N different first relay reception stage interference-removed real data in
1:1 correspondence in a first time slot (S80'').

[0177]The first RS provides the second RS with N different first relay
real data produced by removing the second transmit antenna interference
from the N different first relay amplification real data (S90'').

[0178]The first RS receives N different first BS real data from the first
BS in time division in a second time slot (S100'').

[0179]The second RS generates N different second relay reception stage
interference-removed real data by removing the second receive antenna
interference from the transmitted N different first relay real data
(S110'').

[0180]The second RS generates N different second relay amplification real
data re-amplified and converted by applying N different third powers to
the N different second relay reception stage interference-removed real
data in 1:1 correspondence in a third time slot (S120'').

[0181]The second RS provides at least one selected user MS with N
different second relay real data produced by removing the third transmit
antenna interference from the N different second relay amplification real
data (S130'').

[0182]The second RS receives N different first relay real data from the
first RS in time division in a fourth time slot (S140'').

[0183]Additional operations of devices configured inside the first BS, the
first RS, and the second RS are as follows.

[0184]The first BS internally includes a ZF-DPC unit, a first power
supply, and a first antenna interference detection and removal unit.

[0186]The first power supply generates N different first power real data
amplified and converted by applying N different first powers to the N
user interference-removed real data in 1:1 correspondence.

[0187]The first antenna interference and removal unit generates N
different first BS real data signal-converted by removing first transmit
antenna interference from the N different first power real data.

[0188]The first RS internally includes a second antenna interference
detection and removal unit, a second power supply, and a third antenna
interference and removal unit.

[0189]The second antenna interference detection and removal unit of the
first RS generates N different first relay reception stage
interference-removed real data by removing receive antenna interference
generated by its multiple receive antennas from the N different first BS
real data.

[0190]The second power supply generates N different first relay
amplification real data amplified and converted by applying N different
second powers to the N different first relay reception stage
interference-removed real data in 1:1 correspondence.

[0191]The third antenna interference detection and removal unit generates
N different first relay real data signal-converted by removing second
transmit antenna interference from the N different first relay
amplification real data.

[0192]The second BS internally includes a fourth antenna interference
detection and removal unit, a third power supply, and a fifth antenna
interference detection and removal unit.

[0194]The third power supply generates N different second relay
amplification real data amplified and converted by applying N different
third powers to the N different second relay reception stage
interference-removed real data in 1:1 correspondence.

[0196]According to exemplary embodiments of the present invention, a MIMO
relay system and method perform signal processing to provide requested
real data to at least one selected user MS sequentially connected to a
first RS located in a first cell and a second RS located in a second cell
using spare frequency capacity allocated to a first BS of the first cell
instead of a second BS of the second cell that drops the requested real
data due to its frequency capacity being exceeded, thereby improving
reliability of seamless real data input/output in relay communication,
reducing call drop probability, and raising availability of frequency
capacity by automatically adjusting frequency capacity allocated between
cells.

[0197]While exemplary embodiments of the present invention have been
described above, it will be apparent to those skilled in the art that
various changes and modifications can be made to the described exemplary
embodiments without departing from the spirit or scope of the invention
defined by the appended claims and their equivalents.